Various forms of locking pins are used to lock a post or stud in an opening in various types of fasteners used in types of structural assemblies. The pin must provide a positive lock for personal and equipment protection reasons. Each type of pin is designed to prevent inadvertent or accidental release of the pin from the fastener. Typical examples of prior art devices are described in U.S. Pat. No. 4,592,689, entitled "Ring Spring Cotter," issued to Rue S. Leitzke, on Jun. 3, 1986. This pin is in the form of a figure 8 and lies on top of the bolt to which it is attached. The pin requires bending of the end of the pin to lock the pin in position.
U.S. Pat. No. 4,298,299, entitled "Hairpin Cotter Key," issued to James R. Quarles, on Nov. 3, 1981. This pin may be inserted anywhere along the length of the bolt, however it does not provide a mechanical lock and can be removed by merely pulling the pin off of the bolt.
U.S. Pat. No. 3,175,453, entitled "Locking Pin Assembly Having A Spring Clip," issued to Thomas G. Williams, on Mar. 30, 1965. This pin is also applied by a straight push in and release by a straight pull from the pin.